Ankle foot orthosis

ABSTRACT

An ankle foot orthosis includes a leg member, a foot member, and a drive member. The drive assembly includes a link member which may be hingedly secured to the foot member at a hinge location adjacent to the posterior end of the foot member. The drive assembly may be operable to selectively impart pivotal movement between the foot member and the link member about a first pivot axis, and pivotal movement between the foot member and the leg member about a second pivot axis at the hinge location. The leg member and the foot member strut may be selectively movable in a medial-lateral direction relative to a base of the foot member and the drive assembly. The inferior-superior location of the second pivot axis may be selectively adjustable for substantially aligning the second pivot axis with an axis of rotation of an ankle joint of the wearer.

BACKGROUND

The field of the invention relates generally to an ankle foot orthosis.

In a joint, the range of motion depends upon the anatomy of that jointand on the particular genetics of each individual. Typically, jointsmove in two directions, flexion and extension. Flexion is to bend thejoint and extension is to straighten the joint. However, in theorthopedic convention some joints only flex. For example, the ankle hasdorsiflexion and plantarflexion.

When a joint is injured either by trauma or by surgery, scar tissue canform, often resulting in flexion or extension contractures. Suchconditions can limit the range of motion of the joint, limiting flexion(in the case of an extension contracture) or extension (in the case of aflexion contracture) of the injured joint. It is often possible to treatthis condition by use of a range-of-motion (ROM) orthosis.

ROM orthoses are devices commonly used during physical rehabilitativetherapy to increase the range-of-motion over which the patient can flexor extend the joint. Commercially available ROM orthoses are typicallyattached on opposite members of the joint and apply a torque to rotatethe joint in opposition to the contraction. The force is graduallyincreased to increase the working range or angle of joint motion.

SUMMARY OF THE DISCLOSURE

In one aspect, an ankle foot orthosis generally comprises a leg member,a foot member, and a drive member. The leg member is configured to bereleasably fastened to a leg of the wearer. The foot member isconfigured to be releasably fastened to a foot of a wearer, and the footmember has anterior and posterior ends. The drive assembly includes alink member hingedly secured to the foot member at a hinge locationadjacent to the posterior end of the foot member. The drive assembly isoperable to selectively impart pivotal movement between the foot memberand the link member about a first pivot axis, and pivotal movementbetween the foot member and the leg member about a second pivot axis atthe hinge location.

In another aspect, a method of treating an ankle joint using an anklefoot orthosis generally comprises fastening a foot member of the anklefoot orthosis to a foot of a wearer, and fastening a leg member of theankle foot orthosis to a leg of the wearer. A drive assembly of theankle foot orthosis is configured to impart pivotal movement between alink member of the drive assembly and the foot member about a firstpivot axis located adjacent to a posterior end of the foot member, andto impart pivotal movement between the foot member and the leg memberabout a second pivot axis, to thereby impart one of dorsiflexion andplantarflexion of the ankle joint about a rotational axis.

In yet another aspect, an ankle foot orthosis generally comprises a legmember, a foot member, and a drive assembly. The leg member isconfigured to be releasably fastened to a leg of a wearer. The footmember is configured to be releasably fastened to a foot of the wearer.The foot member is hingedly connected to the leg member for pivotalmovement between the foot member and the leg member about a pivot axis.The drive assembly is operable to selectively impart pivotal movementbetween the foot member and the leg member about the pivot axis. Theinferior-superior location of the pivot axis is selectively adjustablefor substantially aligning the pivot axis with an axis of rotation of anankle joint of the wearer.

In another aspect, an ankle foot orthosis generally comprises a legmember, a foot member, and a drive assembly. The leg member isconfigured to be releasably fastened to a leg of a wearer. The footmember is configured to be releasably fastened to a foot of the wearer.The foot member includes a base and a foot member strut extendingsuperiorly from the base. The foot member strut is hingedly connected tothe leg member for pivotal movement between the foot member and the legmember about a pivot axis. The drive assembly is operable to selectivelyimpart pivotal movement between the foot member and the leg member aboutthe pivot axis. The leg member and the foot member strut are selectivelymovable in a medial-lateral direction relative to the base of the footmember and the drive assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective of one embodiment of an ankle foot orthosis;

FIG. 2 is a left elevational view of the ankle foot orthosis fastened toa foot (in phantom), with straps being removed therefrom forillustrative purposes;

FIG. 3 is a right elevational view of the ankle foot orthosis, withstraps being removed therefrom for illustrative purposes;

FIG. 4 is an exploded view of the ankle foot orthosis, a foot member, aleg member and a drive assembly being exploded from one another;

FIG. 5 is an enlarged, exploded view of the leg member of the ankle footorthosis;

FIG. 6 is an enlarged, exploded view of the foot member of the anklefoot orthosis; and

FIG. 7 is an enlarged, exploded view of the drive assembly of the anklefoot orthosis.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring now to the drawings, and in particular to FIGS. 1-3, an anklefoot orthosis for use in treating an ankle joint (i.e., a talocruraljoint) of a wearer is generally indicated at 10. The illustrated anklefoot orthosis 10 includes a foot member, generally indicated at 12,which is releasably fastenable to a foot F of a wearer, a leg member,generally indicated at 14, which is releasably fastenable to a leg of awearer, and a drive assembly, generally indicated at 16, forfacilitating relative angular movement between the foot member and theleg member. As used in the following description, terms (e.g., inferior,superior, medial, lateral, anterior, and posterior, among others)relating to the locations, positions, and/or directions of components,structures, surfaces, and/or axes, among others, of the ankle footorthosis 10 are human anatomical terms describing relative locations,positions, and/or directions when the ankle foot orthosis 10 is securedto the wearer.

As explained in more detail below, operation of the drive assembly 16provides passive range-of-motion (ROM) treatment or exercise of theankle joint of the wearer. In particular, the illustrated ankle footorthosis 10 facilitates dorsiflexion and plantarflexion of the anklejoint and selective positioning of the ankle in dorsiflexion andplantarflexion. Dorsiflexion is movement of the dorsum (superiorsurface) of the foot F toward the leg about the ankle joint, therebydecreasing the angle between the dorsum of the foot F and the leg.Plantarflexion is movement of the dorsum of the foot F away from theleg, thereby increasing the angle between the dorsum of the foot F andthe leg. As used herein, the ankle joint is in a neutral position whenthe angle between the plantar aspect of the foot F (lying generallywithin an anterior-posterior plane) and a longitudinal axis of the leg(lying generally within an inferior-superior plane) is about 90 degrees.The ankle joint is in a dorsiflexion position when the angle between theplantar aspect of the foot F and the longitudinal axis of the leg isless than about 90 degrees. The ankle joint is in a plantarflexionposition when the angle between the plantar aspect of the foot F and thelongitudinal axis of the leg is greater than about 90 degrees. Therespective degrees of dorsiflexion and plantarflexion of the ankle jointare relative to the neutral position of the ankle joint. As seen in FIG.2, the illustrated ankle foot orthosis 10 is shown fastened to a rightlower limb of the wearer for treating a right ankle joint of the wearer,however, it is understood that the illustrated ankle foot orthosis maybe fastened to a left lower limb of the wearer for treating a left ankleof the wearer.

Referring to FIGS. 1-4 and 6, the foot member 12 includes a heelsecurement assembly 18, and a forefoot securement assembly 20, both ofwhich are connected to a generally rigid base 22. Together, the heelsecurement assembly 18 and the forefoot securement assembly 20constitute a foot securement assembly. Although in the illustratedembodiment the heel and forefoot assemblies 18, 20, respectively, areformed as separate components, the two assemblies may be formed as aone-piece unit within the scope of the present disclosure. The footmember 12 has a longitudinal axis LA₁ (FIG. 3) extending in ananterior-posterior direction. The heel securement assembly 18 isdisposed generally adjacent to a posterior end of the base 22, and theforefoot securement assembly 20 is disposed generally adjacent to ananterior end of the base. In the illustrated embodiment, the heelsecurement assembly 18 includes a heel cup 24, which at least partiallyreceives and supports the heel of the wearer, and a strap 26 (FIGS. 1and 6) secured to the heel cup. In the illustrated embodiment, the heelcup 24 is fixedly secured to the base 22, although the heel cup may beselectively movable (i.e., selectively slidable) on the base to adjustthe position of the heel cup on the base. In the illustrated embodiment,the heel cup 24 has a generally low profile and is sized and shaped suchthat a posterior portion of the heel cup 24 does not contact thewearer's Achilles tendon. The heel cup 24 may include a pad 27 or mayotherwise be provided with cushioning material for comfort.

Referring to FIGS. 1 and 6, the strap 26 of the heel securement assembly18 is extendable over the foot F of the wearer, generally adjacent tothe wearer's ankle, when the wearer's heel is received in the heel cup24 to releasably fasten the cup to the wearer's heel. As seen best inFIG. 6, the illustrated strap 26 is of a two-piece constructionincluding a first strap component 26 a that loops through a D-ring 28 ofa second strap component 26 b. The first strap component 26 a includesfastening components, such as hook and loop components, so that thestrap 26 is adjustable and may be tightened over the wearer's foot F. Apad or other cushioning component may be provided on the strap 26 toprovide comfort. The heel securement assembly 18 may have otherconfigurations, and other ways of releasably fastening the foot member12 to the heel of the wearer are within the scope of the presentdisclosure.

Referring to FIGS. 1-4 and 6, the forefoot securement assembly 20includes a forefoot plate 32 for supporting the forefoot of the wearer,and a strap 34 (FIGS. 1 and 6) secured to the forefoot plate. Theforefoot plate 32 includes a pad 35, which has a generally planarsupport surface on which the forefoot of the wearer rests. Theillustrated pad 35 provides cushioning and comfort to the person,although the forefoot plate 32 may not include a cushioning pad. In theillustrated embodiment, the forefoot plate 32 is selectively movable onthe base 22 in an anterior-posterior direction to accommodate feethaving different lengths. As seen best in FIGS. 2, 3 and 6, the forefootplate 32 is secured to a carriage 36. The carriage 36 includes pins 37that slidably retain the carriage on a flange or rail 38 of the base 22.A locking device (e.g., a thumb screw 39 in the illustrated embodiment)facilitates selective locking of the carriage 36, and thus the forefootplate 32, in a selected anterior-posterior position on the base 22.Other ways of making the forefoot securement assembly 20 selectivelymovable do not depart from the scope of the present disclosure.Moreover, the forefoot securement assembly 20 may not be selectivelymovable without departing from the scope of the present disclosure.

The illustrated strap 34 of the forefoot securement assembly 20 islooped through a D-ring 40 attached to the forefoot plate 32. The strap34 includes a releasable fastening component, such as hook and lookcomponents, to adjustably tighten the strap and releasably fasten theforefoot of the wearer to the plate 32. The forefoot securement assembly20 may have other configurations, and other ways of releasably fasteningthe forefoot of the wearer to the foot member 12 are within the scope ofthe present disclosure.

Referring particularly to FIG. 6, the base 22 of the foot member 12 maybe formed from a rigid plastic material or from another suitablematerial. In one embodiment, the base 22 is constructed to supportweight of a wearer's lower limb when the wearer is seated and the baseis contacting a floor or other foot support surface, as this is thepreferred position of the wearer when treating the ankle joint using theankle foot orthosis 10. It is understood, however, that the wearer maybe in a lying position or another position while the ankle foot orthosis10 applies treatment. An outsole member 41 is secured to a bottom (i.e.,inferior surface) of the base 18. The outsole member 20 is made of asuitable material, such as non-skid polyethylene or other suitablematerial, to inhibit the foot member 12 from sliding on the floor orother foot support surface.

In the illustrated embodiment, the bottom surface of the base 22 hasposterior and anterior portions, 42, 44, respective. The posteriorportion 42 extends from adjacent the posterior end of the base 22 to alocation intermediate the posterior and anterior ends of the base. Theposterior portion 42 is generally planar and is intended to contact andrest on a planar floor or other support surface. In the illustratedembodiment, the posterior portion 42 lies in a plane that is angularlyoffset from (i.e., non-parallel to) the plane defined by the supportsurface of the forefoot securement assembly 20 (e.g., the superiorsurface of the pad 35). For example, the posterior portion 42 may lie ina plane that is angularly offset between about 10° and about 30°. Inthis way, when the foot F of the wearer is fastened to the ankle footorthosis 10 and the contact portion 42 of the bottom surface of the base22 is resting on a planar support surface, the foot F extends upward atan angle relative to the planar support surface that is substantiallyequal to the angular offset between the posterior portion 42 and theplane defined by the support surface of the forefoot securement assembly20. The anterior portion 44 of the bottom surface of the base 22 extendsfrom adjacent the posterior portion 42 to adjacent the anterior end ofthe base. The anterior portion 44 is generally convex or arcuate toenhance strength of the base 22. It is understood that the bottomsurface of the base 22, and the base in general, may be of otherconfigurations without departing from the scope of the presentdisclosure.

Referring to FIGS. 1-5, the leg member 14 includes a leg cuff 48 adaptedto receive and partially encircle a circumference of a leg of thewearer, and a pair of straps 50 (FIG. 1) secured to the leg cuff forreleasably fastening the leg cuff to the leg. The leg cuff 48 has alongitudinal axis LA₂ (FIG. 3) extending in an inferior-superiordirection and extends along the length of the wearer's leg when the cuffis fastened to the leg. The leg cuff 48 may be formed from plastic orother material and include a pad 52, or other cushioning material, toprovide comfort to the person. Each strap 50 is looped through a D-ring54 secured to the leg cuff 48, and each strap includes releasablefastening components, such as hook and loop components, so that thestraps are adjustable to tighten the straps over the wearer's leg. Theleg member 14 may be of other configurations, and other ways ofreleasably fastening the leg member 14 to the leg of the wearer arewithin the scope of the present disclosure.

Referring still to FIGS. 1-5, the leg member 14 includes a strut 62attached to a side of the leg cuff 48, and a bracket 64 connecting theleg member strut to the drive assembly 16. The leg member strut 62 isgenerally rigid and elongate, and may be made from metal or othermaterial. The leg member strut 62 is fixedly secured to, such as byfasteners (e.g., screws), the side of the leg cuff 48, and is fixedlysecured to the bracket 64, such as by screws 65 (FIG. 5) or otherfasteners or in other ways. Although the leg member strut 62 issubstantially rigid, the strut has a bendable portion 66 adjacent to thebracket 64. The bendable portion 66 is pre-bent and bendable in agenerally medial-lateral direction to accommodate wearers havingdifferent degrees of varus/valgus of the knee. Although the illustratedankle foot orthosis 10 includes a single leg member strut 62, in anotherembodiment the ankle foot orthosis may include one or more additionalleg member struts secured to the other side of the leg member 14 or atother locations on the leg member without departing from the scope ofthe present disclosure.

As seen best in FIGS. 1 and 5, the illustrated bracket 64 is generallyL-shaped having a lateral portion (broadly, a first portion) extendingposteriorly from the leg member strut 62, and a posterior portion(broadly, a second portion) extending medially from a posterior end ofthe lateral portion. As seen best in FIGS. 1-3, the leg member strut 62is fixedly attached to the lateral portion of the bracket 64, and theposterior portion of the bracket is slidably attached to a bracketsecurement component 70 of the drive assembly 16. More specifically, theposterior portion of the bracket 64 is slidably received in aslot-shaped opening 71 (FIG. 4) of the bracket securement component 70,whereby the bracket 64 is capable of selectively sliding laterallyrelative to the drive assembly 16. A locking device, which is in theform of a set screw 72 in the illustrated embodiment, facilitatesselective locking and unlocking of the bracket 64 in a selectedmedial-lateral position relative to the drive assembly 16. Through thisconfiguration and for purposes explained in more detail below, the legmember 14 is capable of moving in a medial-lateral direction relative tothe foot member 12 and the drive assembly 16. Other ways of allowing theleg member 14 to be selectively moved in the medial-lateral directionrelative to the foot member 12 and the drive assembly 16 do not departfrom the scope of the present disclosure. Moreover, it is understoodthat the leg member 14 may not be selectively movable in themedial-lateral direction relative to the foot member 12 and the driveassembly 16 without departing from the scope of the present disclosure

Referring now to FIGS. 1-4 and 6, the illustrated foot member 12includes a strut, generally indicated at 74, that is hingedly secured tothe bracket 64, more specifically the lateral portion of the bracket, toallow for pivotal movement between the leg member 14 and the foot member12 about a pivot axis PA₁ (FIGS. 3 and 4). As explained in more detailbelow, the pivot axis PA₁ lies in a generally medial-lateral plane andis preferably substantially coaxial with the rotational axis of theankle joint during use. The foot member strut 74 is generally L-shapedand extends from the bracket 64 to the base 22 of the foot member 12,below (inferior to) the heel cup 24. The foot member strut 74 isconstructed as a two-piece assembly, including a superior component 76(broadly, a first component) and an inferior component 78 (broadly, asecond component). The superior component 76 is hingedly secured, suchas by a shoulder screw 80 or a pin, to the lateral portion of thebracket 64. It is understood that the foot member strut 74 may behingedly secured to the leg member strut 62 in an embodiment which doesnot include the bracket 64. It is understood that the ankle footorthosis 10 may not include the foot member strut and/or the leg memberstrut 62 without departing from the scope of the present disclosure. Insuch an example, the leg member 14 and the foot member 12 would still bepivotable, relative to one another, about the pivot axis PA₁, but theleg member and the foot member would not be hingedly connected to oneanother at the pivot axis.

In the illustrated embodiment, the superior component 76 is selectivelyslidable relative to the inferior component 78 in a generallyinferior-superior direction to facilitate selective alignment of thepivot axis PA₁ with the rotational axis of the ankle joint. Aligning thepivot axis PA₁ with the rotational axis of the ankle joint reduces anklecompression and minimizes the occurrence of the heel lifting off theheel cup 24 during operation of the drive assembly 16. The superiorcomponent 76 is lockable in a selected inferior-superior position usinga locking device 81, which in the illustrated embodiment is in the formof a screw received in a slot-shaped opening 82 of the superiorcomponent. A malleolus pad 83 is attached to the inner side of thesuperior component at the pivotal axis to provide comfort and preventchaffing of skin at the ankle. In the illustrated embodiment, themalleolus pad 83 is positioned adjacent the lateral malleolus LM,although it is understood that in other embodiments the malleolus padmay be adjacent the medial malleolus. It is understood that the footmember strut 74 may be a one-piece component and/or non-adjustable inlength in the inferior-superior direction without departing from thescope of the present disclosure.

The inferior component 78 is generally L-shaped and is slidablyconnected to the base 22 of the foot member 12. The inferior component78 is received in a track 84 defined by the base and is freely slidablerelative to the foot member 12 such that medial-lateral movement of thebracket 64 imparts sliding medial-lateral movement of the foot memberstrut 74 relative to the foot member. Thus, the leg cuff 48, the legmember strut 66, the bracket 64, and the foot member strut 74 aremovable together in a medial-lateral direction. In this way, the anklefoot orthosis 10 can be adjusted based on the thickness (i.e., amedial-lateral dimension) of the lateral portion of the wearer's lowerleg and ankle to facilitate proper positioning of the wearer's heel andforefoot on the foot member 12. For example, the wearer may haveswelling (i.e., edema) of the ankle and/or an ankle wrap or bandagearound his/her ankle. In such a situation, the bracket 64 may be slidrelative to the bracket securement component 70 to allow the wearer toproperly position his/her heel and forefoot on the foot member 12.

In the illustrated embodiment, the base 22 has two tracks 84 on oppositesides of the base, although only one of the tracks is used, depending onwhether the orthosis is configured for the right ankle or the leftankle. In this way, the base is modular, wherein only one type of baseneeds to be manufactured for both a right ankle foot orthosis and a leftankle foot orthosis. In a left ankle foot orthosis, the foot memberstrut 74 is received in the other track. The inferior component 78 maybe made from plastic or other material. In another embodiment, a lockingdevice (not shown) may be associated with the inferior component 78 toprevent unintended sliding of the inferior component relative to thefoot member 12.

Referring to FIGS. 1-4 and 7, the drive assembly 16 is generally in theform of a rack and pinion drive assembly. Accordingly, the driveassembly 16 includes a rack 85, and a pinion 86 operably coupled to therack. The ankle foot orthosis 10 may include other types of driveassemblies besides the illustrated rack and pinion drive assembly 16.The rack 85, which broadly constitutes a link member, is hingedlysecured to the foot member 12 at a securement location generallyadjacent to the posterior end of the base 22. The rack 85 is hingedlyconnected to the foot member 12 by a pin 88 so that the rack ispivotable about a pivot axis PA₂ (FIGS. 1 and 3). The rack 85 may behingedly secured to the foot member 12 in other ways. The rack 85 isgenerally elongate, having a longitudinal axis LA₃ (FIG. 3) extendingslightly posteriorly from adjacent the posterior end of the base 22 ofthe foot member 12 and superiorly toward the leg cuff 48. Thelongitudinal axis LA₃ of the rack 85 is disposed posterior to the heelcup 24 and the leg member 14, and is generally coplanar with thelongitudinal axis LA₁ of the foot member 12, such that when the wearer'sheel is fastened to the heel cup 24, the Achilles tendon of the weareris also generally coplanar with the longitudinal axis LA₃ of the rack85.

The rack 85 includes a plurality of teeth 90 extending substantiallylinearly along the length of the rack. The pinion 86 operably enages theteeth 90 of the rack 85, whereby rotation of the pinion imparts relativemovement between the pinion and the rack, which, in turn, impartspivotal movement between the rack and the foot member 12 about the pivotaxis PA₂ and imparts pivotal movement between the foot member and theleg member 14 about the pivot axis PA₁, as explained in more detailbelow. In the illustrated embodiment, the teeth 90 define a linearlongitudinal axis that is generally coplanar with the longitudinal axisLA₁ of the foot member 12, and when the wearer's heel is fastened to theheel cup 24, the teeth are generally coplanar with the Achilles tendonof the wearer. Through the configuration and position of the driveassembly 16, the drive assembly provides a force directly to the footmember 12 to create a moment about the pivot axis PA₁ and the rotationalaxis of the ankle joint.

As seen best in FIG. 7, rotation of the pinion 86 is driven by amanually rotatable input shaft 94 secured to a gear box 95 that isslidably secured to the rack 85 and moves with the rack. In theillustrated embodiment, the bracket securement component 70 is attachedto the gear box 95 and moves with the gear box. The gear box 95 and therack 85 are pivotable relative to one another about a pivot axis PA₃. Assuch, rotation of the pinion 86 also imparts relative pivotal movementbetween the gear box 95 (and the securement component 70) and the rack85. The input shaft 94 has a knob 96 secured at a superior longitudinalend and a worm 98 secured at an inferior longitudinal end, which isreceived in the gear box 95. The input shaft 94 extends superiorly fromthe gear box 95 at a lateral angle relative to the longitudinal axis LA₃of the rack 85. Through this configuration, the knob 96 is adjacent thelateral side of the leg cuff 48, as positioned on the right lower limbin the illustrated embodiment, so that the knob 96 is accessible to thewearer using his/her right hand, in the illustrated embodiment, when thewearer is seated. It is understood that the knob 96 may be adjacent themedial side of the leg cuff 48, as positioned on a right lower limb or aleft lower limb, without departing from the scope of the presentinvention. Within the gear box 95, the worm 98 operably engages a wormgear 100, which is coaxially secured to the pinion 86 via a drive shaft102 (e.g., a hexagonal shaft). The worm gear 100 has a diameter largerthan the diameter of the pinion 86 to provide a mechanical advantage. Abushing 104 for the drive shaft 102 is disposed between the worm gear100 and the pinion 86. The drive shaft 102 passes through the bushing104 and a spacer 106 that spaces the bushing apart from the worm gear100. The bushing engages the inner surface of the gear box 95 to inhibitcanting or slanting of the drive shaft, thereby retaining the worm gear100 and the pinion 86 in operative engagement with the worm 98 and therack 85, respectively. The drive assembly 16 may have otherconfigurations without departing from the scope of the presentdisclosure.

In one exemplary method of using the ankle foot orthosis 10, thewearer's foot F and leg are placed in the orthosis. The wearer's foot Fis placed in the orthosis 10 by placing the heel in the heel cup 24 andplacing the forefoot on the forefoot plate 32. The forefoot plate 32 maybe slidably adjusted, such as by loosening the set screw 36 and slidingthe forefoot plate on the base 22, so that the strap 34 extends over thetoes and the toes do not extend past the anterior edge of the plate. Thewearer's leg is inserted into the leg cuff 48, such as by spreadingapart the lateral and medial sides to allow the leg to enter the cuff.The medial-lateral position of the leg cuff 48, the bracket 64, and thefoot member strut 74 relative to the wearer's foot F (and the footmember 12 and the drive assembly 16) may be adjusted to accommodate thethickness of the inferior portion of the wearer's leg and ankle. The setscrew 72 is loosened to allow the bracket 64 to slide freely relative tothe bracket securement component 70. When the leg cuff 48, the bracket64, and the foot member strut 74 are in the selected medial-lateralposition, the set screw 72 is tightened.

The inferior-superior position of the pivot axis PA₁ can be adjusted ifthe pivot axis is not substantially coaxial with the rotational axis ofthe ankle joint. The inferior-superior position of the pivot axis PA₁ isadjusted by loosening the screw 81 connecting the superior component 76to the inferior component 78 of the foot strut 66, and then sliding thesuperior component either superiorly or inferiorly relative to theinferior component. The screw 81 is tightened when the pivot axis PA₁ iscoaxial with the rotational axis of the ankle joint. Alignment of thepivot axis PA₁ with the rotational axis of the ankle joint may beaccomplished by substantially aligning the pin 80, and the malleolus pad83 with the lateral malleolus LM, in the illustrated embodiment, or themedial malleolus in another embodiment.

After the confirming that the wearer's leg and foot F are properlypositioned in the ankle foot orthosis 10, the straps 26, 34 of the footmember 12 and the straps 50 of the leg member 48 are tightened to fastenthe ankle foot orthosis to the foot F and leg of the wearer. With theankle foot orthosis 10 fastened to the wearer's leg and foot F and thewearer preferably seated, the knob 96 is rotated, either by the weareror another person, to provide passive range-of-motion (ROM) exercise ofthe ankle joint. In particular, rotation of the knob 96 in a selecteddirection decreases the spacing between the pinion 86 and the pivot axisPA₂, causing respective pivoting movement between the rack 85 and thefoot member 12 about the pivot axis PA₂, and between the bracket 64 (andthe leg cuff 48) and the foot member 12 about pivot axis PA₁, to therebyimpart plantarflexion of the ankle joint. Rotation of the knob 96 in aselected, opposite direction increases the spacing between the pinion 86and the pivot axis PA₂, causing respective pivoting movement between therack 85 and the foot member 12 about the pivot axis PA₂, and between thebracket 64 (and the leg cuff 48) and the foot member 12 about the pivotaxis PA₁, to thereby impart dorsiflexion of the ankle joint. In oneembodiment, the drive assembly 16 of the ankle foot orthosis 10 isconfigured to facilitate movement and positioning of the ankle jointfrom about 0 degrees to about 40 degrees of dorsiflexion and from about0 degrees to about 52 degrees of plantarflexion.

In one treatment protocol, the ankle joint may be moved to a firstposition in one of dorsiflexion and plantarflexion for a predeterminedamount of time (e.g., about 5 minutes), and then the drive assembly 16is operated to move the ankle joint to a second position in said one ofdorsiflexion and plantarflexion of another predetermined amount of time(e.g., another 5 minutes). The drive assembly 16 may also be operated tomove the ankle joint any number of subsequent positions. Maintaining theankle joint in the first and second positions and any other subsequentpositions for the predetermined amount of time allows connective tissueof the ankle joint to be stretched. In particular, this type oftreatment utilizes the principles of stress relaxation to stretch theconnective tissue of the joint. In another embodiment, the ankle footorthosis 10 may also be configured to provide a dynamic stretch to theankle joint.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

1. An ankle foot orthosis comprising: a leg member configured to bereleasably fastened to a leg of the wearer; a foot member configured tobe releasably fastened to a foot of a wearer, the foot member havinganterior and posterior ends; and a drive assembly including a linkmember hingedly secured to the foot member at a hinge location adjacentto the posterior end of the foot member, the drive assembly operable toselectively impart pivotal movement between the foot member and the linkmember about a first pivot axis, and pivotal movement between the footmember and the leg member about a second pivot axis at the hingelocation.
 2. The ankle foot orthosis set forth in claim 1, wherein thelink member has a substantially linear longitudinal axis extendinggenerally superiorly from the hinge location.
 3. The ankle foot orthosisset forth in claim 2, wherein the link member comprises a rack having aplurality of linearly aligned teeth, and wherein the drive assemblyfurther comprises a pinion gear operably coupled to the rack forrelative movement therewith to impart said pivotal movement between thefoot member and the link member about the first pivot axis and saidpivotal movement between the foot member and the leg member about thesecond pivot axis.
 4. The ankle foot orthosis set forth in claim 3,wherein the drive assembly includes a rotatable input shaft forimparting rotation to the pinion, the input shaft configured to bemanually rotatable by hand.
 5. The ankle foot orthosis set forth inclaim 4, wherein the drive assembly includes a worm fixedly secured tothe drive shaft, the worm operably coupled to the pinion gear fortransmitting rotational force to the pinion.
 6. The ankle foot orthosisset forth in claim 1 wherein the foot member has a longitudinal axisextending between the anterior and posterior ends thereof, wherein thelongitudinal axis of the link member and the longitudinal axis of thefoot member are substantially coplanar.
 7. The ankle foot orthosis setforth in claim 1, wherein the foot member and the leg member arehingedly connected to one another for relative pivotal movement aboutthe second pivot axis.
 8. The ankle foot orthosis set forth in claim 7,wherein the leg member comprises a bracket slidably secured to the driveassembly to allow for sliding movement of the bracket relative to thedrive assembly in the medial-lateral direction, the foot membercomprising a base and a strut slidably connected to the base, andhingedly connected to the bracket for relative pivotal movement aboutthe second pivot axis, wherein sliding movement of the bracket relativeto the drive assembly in the medial-lateral direction imparts slidingmovement of the strut of the foot member relative to the base of thefoot member.
 9. The ankle foot orthosis set forth in claim 8, furthercomprising a bracket locking device for engaging the bracket andselectively locking the bracket and the foot member strut in a selectedmedial-lateral position, and for selectively unlocking the bracket toallow medial-lateral movement of the bracket relative to the driveassembly.
 10. The ankle foot orthosis set forth in claim 1, wherein aninferior-superior position of the second pivot axis is selectivelyadjustable for substantially aligning the second pivot axis with theaxis of rotation of the ankle joint.
 11. The ankle foot orthosis setforth in claim 10, wherein the foot member includes a strut memberhingedly secured to the leg member for rotation about the second pivotaxis, wherein the strut member is adjustable in length in theinferior-superior direction to adjust the inferior-superior position ofthe second pivot axis.
 12. The ankle foot orthosis set forth in claim 1,wherein the foot member includes a base, and a heel securement assemblysecured on the base for fastening to a heel of the wearer, wherein thelink member is disposed posterior of the heel securement assembly and ishingedly secured to the base at the hinge location.
 13. The ankle footorthosis set forth in claim 12, wherein the drive assembly includes amanually operable input shaft having a knob disposed posterior of theleg member and generally adjacent a lateral side thereof
 14. The anklefoot orthosis set forth in claim 1, wherein the first pivot axis isdisposed posterior of the second pivot axis.
 15. The ankle foot orthosisset forth in claim 14, wherein the first pivot axis is disposed inferiorto the second pivot axis.
 16. The ankle foot orthosis set forth in claim15, wherein the first pivot axis is generally parallel to the secondpivot axis.
 17. A method of treating an ankle joint using an ankle footorthosis, the method comprising: fastening a foot member of the anklefoot orthosis to a foot of a wearer; fastening a leg member of the anklefoot orthosis to a leg of the wearer; and operating a drive assembly ofthe ankle foot orthosis to impart pivotal movement between a link memberof the drive assembly and the foot member about a first pivot axislocated adjacent to a posterior end of the foot member, and to impartpivotal movement between the foot member and the leg member about asecond pivot axis, to thereby impart one of dorsiflexion andplantarflexion of the ankle joint about a rotational axis.
 18. Themethod set forth in claim 17, wherein said operating a drive assemblycomprises manually rotating an input shaft of the drive assembly. 19.The method set forth in claim 18, wherein the drive assembly comprises arack and pinion drive assembly, wherein said operating a drive assemblycomprises rotating a pinion gear of the drive assembly to impartrelative movement between the pinion gear and a rack of the rack andpinion drive assembly.
 20. The method set forth in claim 17, furthercomprising adjusting an inferior-superior position of the second pivotaxis such that the second pivot axis is substantially coaxial with therotational axis of the ankle joint.
 21. The method set forth in claim17, further comprising moving the leg member relative to the foot memberto adjust a medial-lateral position of the leg member.
 22. An ankle footorthosis comprising: a leg member configured to be releasably fastenedto a leg of a wearer; a foot member configured to be releasably fastenedto a foot of the wearer, the foot member hingedly connected to the legmember for pivotal movement between the foot member and the leg memberabout a pivot axis; and a drive assembly operable to selectively impartpivotal movement between the foot member and the leg member about thepivot axis, wherein the inferior-superior location of the pivot axis isselectively adjustable for substantially aligning the pivot axis with anaxis of rotation of an ankle joint of the wearer.
 23. The ankle footorthosis set forth in claim 22, wherein the foot member includes a footmember strut hingedly secured to the leg member, the foot member strutselectively adjustable in length extending in an inferior-superiordirection to selectively adjust the pivot axis.
 24. The ankle footorthosis set forth in claim 23, wherein the foot member strut comprisesan inferior component and a superior component selectively slidable onthe inferior component in the inferior-superior direction.
 25. The anklefoot orthosis set forth in claim 24, wherein the foot member furtherincludes a base, the inferior component selectively slidable in amedial-lateral direction relative to the base of the foot member. 26.The ankle foot orthosis set forth in claim 25, wherein the leg memberincludes a bracket slidably secured to the drive assembly to allow forsliding movement of the bracket relative to the drive assembly in themedial-lateral direction, wherein sliding movement of the bracketrelative to the drive assembly in the medial-lateral direction impartssliding movement of the foot member strut relative to the base of thefoot member.
 27. An ankle foot orthosis comprising: a leg memberconfigured to be releasably fastened to a leg of a wearer; a foot memberconfigured to be releasably fastened to a foot of the wearer, the footmember including a base and a foot member strut extending superiorlyfrom the base, wherein the foot member strut is hingedly connected tothe leg member for pivotal movement between the foot member and the legmember about a pivot axis; and a drive assembly operable to selectivelyimpart pivotal movement between the foot member and the leg member aboutthe pivot axis, wherein the leg member and the foot member strut areselectively movable in a medial-lateral direction relative to the baseof the foot member and the drive assembly.
 28. The ankle foot orthosisset forth in claim 27, wherein the leg member includes a bracket securedto the drive assembly, wherein the bracket is selectively slidable inthe medial-lateral direction relative to the drive assembly.
 29. Theankle foot orthosis set forth in claim 28, further comprising a bracketlocking device for engaging the bracket and selectively locking thebracket and the foot member strut in a selected medial-lateral position,and for selectively unlocking the bracket to allow medial-lateralmovement of the bracket and the foot member strut.